1. Field of the Invention
This invention relates generally to an industrial process, and, more particularly, to various methods and systems for scheduling maintenance procedures based upon workload distribution.
2. Description of the Related Art
There is a constant drive within the semiconductor industry to increase the quality, reliability and throughput of integrated circuit devices, e.g., microprocessors, memory devices, and the like. This drive is fueled by consumer demands for higher quality computers and electronic devices that operate more reliably. These demands have resulted in a continual improvement in the manufacture of semiconductor devices, e.g., transistors, as well as in the manufacture of integrated circuit devices incorporating such transistors. Additionally, reducing the defects in the manufacture of the components of a typical transistor also lowers the overall cost per transistor as well as the cost of integrated circuit devices incorporating such transistors.
Generally, a set of processing steps is performed on a lot of wafers using a variety of process tools, including photolithography steppers, etch tools, deposition tools, polishing tools, thermal anneal process tools, ion implantation tools, etc. The technologies underlying semiconductor process tools have attracted increased attention over the last several years, resulting in substantial refinements. However, despite the advances made in this area, many of the process tools that are currently commercially available suffer certain deficiencies. In particular, some of such tools often lack advanced process data monitoring capabilities, such as the ability to provide historical parametric data in a user-friendly format, as well as event logging, real-time graphical display of both current processing parameters and the processing parameters of the entire run, and remote, i.e., local site and worldwide, monitoring. These deficiencies can engender non-optimal control of critical processing parameters, such as throughput, accuracy, stability and repeatability, processing temperatures, mechanical tool parameters, and the like. This variability manifests itself as within-run disparities, run-to-run disparities and tool-to-tool disparities that can propagate into deviations in product quality and performance, whereas an ideal monitoring and diagnostics system for such tools would provide a means of monitoring this variability, as well as providing means for optimizing control of critical parameters.
One technique for improving the operation of a semiconductor processing line includes using a factory wide control system to automatically control the operation of the various process tools. The manufacturing tools communicate with a manufacturing framework or a network of processing modules. Each manufacturing tool is generally connected to an equipment interface. The equipment interface is connected to a machine interface that facilitates communications between the manufacturing tool and the manufacturing framework. The machine interface can generally be part of an advanced process control (APC) system. The APC system initiates a control script based upon a manufacturing model, which can be a software program that automatically retrieves the data needed to execute a manufacturing process. Often, semiconductor devices are staged through multiple manufacturing tools for multiple processes, generating data relating to the quality of the processed semiconductor devices.
The tools and processes employed in manufacturing integrated circuit devices are very complex. Even minor variations in tool performance can dramatically and adversely impact the effectiveness of manufacturing processes and ultimately production yields. Accordingly, it is extremely important that the processing tools employed in semiconductor manufacturing environments be maintained to a very high standard. Sophisticated maintenance procedures are often performed on such process tools in an effort to insure that the tools are maintained in peak operational condition.
In many cases, maintenance procedures for the various processing tools found within a semiconductor manufacturing facility are performed on a regimented, or routine basis. For example, a given process tool may be scheduled for pre-planned maintenance activities on a weekly, bi-weekly or monthly basis. When such maintenance procedures are performed, the particular processing tool may be out of service for an extended duration of time, e.g., 12–24 hours. Such a methodology for scheduling maintenance activities may reduce the overall efficiency of the manufacturing facility and/or increase product cycle times. In today's semiconductor manufacturing environment, reducing product cycle times and improving manufacturing efficiencies are critical to the profitable production of integrated circuit devices.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.